The present invention relates to a support structure for a power element, and especially to a simple support structure, which can be easily manufactured so as to reduce costs greatly.
U.S. Pat. No. 5,225,897 discloses a support structure for a power element including a conductive mounting platform, including one envelope engaging member, an interior conductive surface and an exterior conductive surface, for a semiconductor device which has a first electrical contact and a second electrical contact for positioning the semiconductor device on the interior conductive surface of the conductive mounting platform. The support structure also includes an envelope structure secured with the conductive mounting platform by the envelope engaging member. The envelope structure converges as a shell on the semiconductor device and the exterior conductive surface and the envelope engaging member are exposed for heat dissipation. The envelope engaging member includes an exterior wall portion of the envelope structure. The support structure further includes at least one conductive lead with a first end and a second end, wherein the first end is in contact with the second electrical contact of the semiconductor device and the second is located outside the exterior wall portion. A process for packaging the semiconductor device includes steps of forming a lower lead frame for connecting the conductive mounting platform and an upper frame. The conductive mounting platform extends from one side of the lower lead frame toward one side of the upper lead frame. At least one conductive lead is set with the upper lead frame and extends from the upper lead frame to one side of the lower lead frame for installing the semiconductor device to the conductive mounting platform and connecting both the semiconductor device and the conductive mounting platform electrically. The conductive lead is allowed to contact the electrical contacts of the semiconductor device. The envelope engaging member is bent to a predetermined degree, and the envelope structure is formed such that the envelope engaging member is convoluted so as to package the semiconductor device within a protection shell. The conductive mounting platform is then separated from the lower lead frame and the conductive wire separated from the upper lead frame.
But because the connecting element is set on the lower lead frame and the conductive lead is set on the upper lead frame for this kind of support structure, the upper lead frame and the lower lead frame are different in structure and cannot be manufactured efficiently, leading to huge expenditures. Furthermore, the bending of the envelope engaging element to the predetermined degree required, complicates the whole manufacturing procedure and also increases the total costs thereof.
Accordingly, the primary object of the present invention is to provide a support structure for a power element, wherein the connecting element and the conductive lead are formed at two opposite sides of a lead frame. Since only one lead frame is necessary, the defect of prior art with an upper lead frame and a lower lead frame is improved. Therefore, the structure of the present invention is simple, and can be easily manufactured so as to reduce cost greatly.
Another object of the present invention is to provide a support structure of a power element, wherein the envelope engaging member of the present invention is formed with a predetermined bending angle so that it is unnecessary to bend the envelope engaging member during manufacturing. Therefore, the manufacturing process is simplified and thus the expenditure can be lowered down greatly.
In accordance with the claimed invention, the present invention provides a support structure of a power element. A conductive mounting platform of the support structure is directly formed with an envelope engaging member, and at least one connecting element is connected to a first side of the conductive mounting platform and at least one conductive lead with a first end and a second end is set on a second side of the conductive mounting platform. The second end of the conductive lead is connected to the second side of the lead frame. A crossing wire is placed between the first end of the conductive lead and a first electrical contact of the semiconductor device.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following description of the preferred embodiment which is illustrated in the various figures and drawings.